#!/usr/bin/python
# -*- coding: UTF-8 -*-
import matplotlib.pyplot as plot
import numpy as np
x=np.arange(-10,11,1)
y=x**2
plot.plot(x,y)
#arrorw xy  xytext="文字" facecolr color heglenght 箭头的长度 headwidht 箭头的宽度 widht 箭身的宽度
plot.annotate("this is annote",xy=(0,1),xytext=(0,20),arrowprops=dict(facecolor="g",headlength=10,headwidth=8,width=10))
plot.show()
